Silva Laiana O B, Leao Danilo J, dos Santos Debora C, Matos Geraldo D, de Andrade Jailson B, Ferreira Sergio L C
Universidade Federal da Bahia, Instituto de Química, CEP 40170-270, Salvador-Bahia, Brazil.
Instituto Nacional de Ciência e Tecnologia, INCT, de Energia e Ambiente, Universidade Federal da Bahia, 40170-290 Salvador-BA, Brazil.
Talanta. 2014 Sep;127:140-5. doi: 10.1016/j.talanta.2014.04.010. Epub 2014 Apr 13.
The present paper describes the development of a method for the determination of copper in airborne particulate matter using slurry sampling and chemical vapor generation atomic absorption spectrometry (CVG AAS). Chemometric tools were employed to characterize the influence of several factors on the generation of volatile copper species. First, a two-level full factorial design was performed that included the following chemical variables: hydrochloric acid concentration, tetrahydroborate concentration, sulfanilamide concentration and tetrahydroborate volume, using absorbance as the response. Under the established experimental conditions, the hydrochloric acid concentration had the greatest influence on the generation of volatile copper species. Subsequently, a Box-Behnken design was performed to determine the optimum conditions for these parameters. A second chemometric study employing a two-level full factorial design was performed to evaluate the following physical factors: tetrahydroborate flow rate, flame composition, alcohol volume and sample volume. The results of this study demonstrated that the tetrahydroborate flow rate was critical for the process. The chemometric experiments determined the following experimental conditions for the method: hydrochloric acid concentration, 0.208 M; tetrahydroborate concentration, 4.59%; sulfanilamide concentration, 0.79%; tetrahydroborate volume, 2.50 mL; tetrahydroborate flow rate, 6.50 mL min(-1); alcohol volume, 200 µL; and sample volume, 7.0 mL. Thus, this method, using a slurry volume of 500 µL and a final dilution of 7 mL, allowed for the determination of copper with limits of detection and quantification of 0.30 and 0.99 µg L(-1), respectively. Precisions, expressed as RSD%, of 4.6 and 2.8% were obtained using copper solutions at concentrations of 5.0 and 50.0 µg L(-1), respectively. The accuracy was evaluated by the analysis of a certified reference material of urban particulate matter. The copper concentration obtained was 570±63 mg kg(-1), and the certified value was 610±70 mg kg(-1). This method was applied for the determination of copper in airborne particulate matter samples collected in two Brazilian regions of Bahia State, Brazil. The copper contents found varied from 14.46 to 164.31 ng m(-3).
本文描述了一种采用悬浮液进样和化学蒸气发生原子吸收光谱法（CVG AAS）测定空气中颗粒物中铜的方法的开发。运用化学计量学工具来表征几个因素对挥发性铜物种生成的影响。首先，进行了一个二水平全因子设计，其中包括以下化学变量：盐酸浓度、硼氢化四钠浓度、磺胺浓度和硼氢化四钠体积，以吸光度作为响应值。在既定的实验条件下，盐酸浓度对挥发性铜物种的生成影响最大。随后，进行了Box-Behnken设计以确定这些参数的最佳条件。进行了第二项采用二水平全因子设计的化学计量学研究，以评估以下物理因素：硼氢化四钠流速、火焰组成、乙醇体积和样品体积。该研究结果表明硼氢化四钠流速对该过程至关重要。化学计量学实验确定了该方法的以下实验条件：盐酸浓度0.208 M；硼氢化四钠浓度4.59%；磺胺浓度0.79%；硼氢化四钠体积2.50 mL；硼氢化四钠流速6.50 mL min⁻¹；乙醇体积200 μL；样品体积7.0 mL。因此，该方法使用500 μL的悬浮液体积和最终7 mL的稀释倍数，能够测定铜，其检测限和定量限分别为0.30和0.99 μg L⁻¹。使用浓度为5.0和50.0 μg L⁻¹的铜溶液分别获得了4.6%和2.8%的相对标准偏差（RSD%）表示的精密度。通过分析城市颗粒物的有证标准物质评估了准确度。获得的铜浓度为570±63 mg kg⁻¹，认定值为610±70 mg kg⁻¹。该方法应用于巴西巴伊亚州两个地区采集的空气中颗粒物样品中铜的测定。所发现的铜含量在14.46至164.31 ng m⁻³之间变化。
